Component characteristic tester with BLE based on ch579

Component characteristic testing is a very important skill point and will be examined in various forms in every national college student electronic design competition.

This circuit refers to the German open source project AVR Transistor Tester, and the Lichuang platform open source project https://oshwhub.com/micespring/m328-transistor-tester, https://oshwhub.com/asxs/jing-ti-guan-ce- Shi-yi , etc., are made using ch579 chips, with dual-channel LDO optional power supply.

AVR source code and binary see attachment

1 Design purpose

(1) Measuring diode;

(2) Measure resistance;

(3) Measure capacitance;

(4) Measure the polarity of the triode.

2 Functions and requirements

(1) Component characteristic testing;

(2) BLE function;

(3) Lead to serial port/SPI and other IO port expansion;

(1) Display module;

The display module has three outputs:

1. The first channel is the i2c interface. Since ch579 does not have i2c, it uses gpio port B8/B9 simulation, and combines 3.3v and gnd to drive an "I2C - OLED 0.96" module. The design and initialization source code is as follows

2. The second path is the host computer with custom protocol for USB interface (under development)

3. The third channel is a full-platform control app/host computer with a custom protocol for the Bluetooth interface (under development)

(2) Measurement module;

Compatible with AVR Transistor Tester’s J1, J2, J3 pins

(3) Extension module;

1. Reserve serial port rx/tx output. If b8/b9 is not used for i2c output display, it can also be used as SWD download port. At this time, A7 has the rst function. Can be extended with a DAPlink emulator

2. If b8/b9 is not used for i2c output display and is only used as an ordinary i2c port, it can also be used with the 4 pins of the spi port SCK/MOSI/MISO/CS to make a multi-function writer similar to CH341A

4 Welding debugging

(1) Prepare the materials before welding (see BOM list for specific materials), which can effectively reduce the welding debugging time during welding.

(2) After soldering the typec connector, ams1117 and filter capacitor, you can start soldering ch579. This qfn is asymmetrical and tight. For an amateur like me, welding will be very difficult.

After plugging in, wch information will be displayed

Since it is an empty chip, the device can be recognized immediately in WCHISPTool.

After welding the finished product.

Since the 32M crystal oscillator and capacitor are not soldered, CLK_SOURCE_HSE_32MHz needs to be changed to CLK_SOURCE_HSI_32MHz.